Friction unit for railway car trucks



Dec. 29, 1936. v c. D. BARRETT 2,065,992

FRICTION UNIT FOR RAILWAY CAR TRUCKS Filed March 9, 1935 4 Sheets-Sheet l FICA I Q a PE? u w w R M INVENTOR: T/J g Charles llfiarrelifil,

- E L- r I TTORNEYS.

Dec; 29, 1936. c. D. BARRETT FRICTION UNIT FOR RAILWAY CAB TRUCK Filed March 9, 1935 WL JZF56 7 INVENTOR: Charles D. BarrLT/b, a BY I I (TTORNEYS m xii Dec. 29, 1936.

c. D. BARRETT FRICTION UNIT FOR RAILWAY CAR TRUCKS v 4 Sheets-Sheet 5 Filed March 9, 1935 I WW1 TNf/iSi) Dec. 29, 1936. c. D. BARRETT FRICTION UNIT FOR RAILWAY CAR TRUCKS 4 Sheets-Sheet 4 INVENTOR: CZLLLILE/S l7. ELI/77151323, BY

Filed March 9, 1935 WITNESSES.- W/S m TTORNEYS. 5

Patented Dec. 29, 1936 UNITED STATES PATENT OFFICE Application March 9, 1935, .Serial No. 10,241

4 Claims. (01. 105-197) This invention relates to railway car trucks and .more particularly to a friction unit adapted for use incombination with springs for supporting the truck bolster.

Heretofore it has been proposed to increase the spring capacity of car trucks, as well as to improve their riding qualities, by the provision of various combinations of springs and shock absorbing devices. It has long been recognized that the helical springs customarily employed in freight car trucks produce a harmonic motion which causes the car body to rise and fall substantially equal distances above and below its statieposition, with this motion continuing over a relatively long period; and n erous attempts have been made to dampen su vibrations by providing additional springs of a different character or friction gears which serve to break up the harmonic motion of the helical springs.

Many of the proposed arrangements require radical changes in standard truck construction, such as the provision of new types of bolsters or side frames; others involve the use'of relatively large and ineflicient springs which are objectionable because of the limited space available in the windows of the side frames; and still other arrangements involve the use ,of friction units, in

substitution for' one or more spring units, which are characterized by friction elements having interengaging surfaces of relatively small area, and which can obtain-a large load-carrying capacity only by employing friction elements which tend to stick if the coeflicient of friction is high..

The object of the present invention is to avoid the above recited difficulties, and this end is accomplished by the provision of a novel form of shock absorbing unit which is adapted to take;

the place of a spring unit, and which thus may be inserted in trucks of standard construction without requiring changes in the form of the bolster or side frames. The shock absorbing unit of this' invention is further characterized by friction elements having relatively large surfaces and a spring for opposing movement of the friction elements and preventing the device from sticking,

the spring being disposed in such manner as to project outside the window opening of the side frame and thus not to interfere with the space desired for the insertion of the coil spring units.

the description having reference to the accompanying drawings, whereof:

Fig. I represents a side elevation of a railway car truck embodying my invention.

Fig. II represents a view of the same, partly in end elevation and partly in section, showing the .arrangement of the bolster, spring plank, and side frames.

Fig. 111 represents an enlarged cross section, taken as indicated by the line III-III of Fig. I, showing details of the friction unit and the manner in which it is seated in position in the side frame? Fig. IV represents an enlarged cross section, taken as indicated by the line IV-IV of Figs. I" and III, showing further details of a portion of the friction unit.

, Fig. V represents a horizontal cross section, taken as indicated by the line V.V of Fig. m.

Fig. VI represents 'a cross section, taken as indicated by the line VI-VI of Fig. IIand showing a plan view of the coil springs and friction unit of one side frame.

Fig. VII represents a vertical cross section of the friction unit, taken as indicated by the line VIIVII of Fig. III.

Fig. VIII represents a vertical cross section of the friction unit, taken as indicated by the line VIIIVIII ofFigs. II and III; and

Fig. IX represents an exploded view of parts of I I. The tension members 2 include a web or seat portion 7 upon which is mounted a group of shock absorbing elements comprising helical springs 8a, 8b and a self-contained friction unit comprehensively designated at 9. In the illustrated example there are three sets of coil springs and one friction unit for each side frame, and each set of coil springs comprises an inner spring 8b and an outer spring 8a. A bolster l0 extends between the side frames 5', with its ends supported upon the helical springs 8a, 8b and upon the friction units 9. A spring plank I I, or other connecting member of like nature, joins one side frame I with the other beneath the bolster II).

It will be observed that the arrangement shown in Figs. I and II represents a conventional form of railway car truck, with a self-contained friction unit 3 of this invention substituted for one set of coil springs in each side frame. As will be more fully apparent from the description hereinafter, this friction unit, though it is especially adapted for application to trucks of standard construction, may be applied to many different types of car trucks.

Each friction unit 3 is disposed vertically and flexibly mounted, in a manner similar to the coil springs 8a, 8b, with its base supported on the seat portion 1 of the side frame and with its top engaging the bolster l3. Each friction unit 3 comprises a series of wedge members in frictional engagement with each other and springsopposing relative movement of the wedge members. The wedge members include a pair of vertically movable members I411, I41) and a pair of horizontally movable members |6a llib. The springs opposing relative movement of the wedge members conveniently comprise a relatively heavy outer spring |8a. and a relatively light inner spring l8b. All of the springs and wedge members of the unit are held in assembled relation by means of a horizontal securing bolt 23 and a pair of verticall disposed bolts 2 I.

For transmitting the'load of the bolster ID to the wedge members |4a, |4b, I6a, |6b,'bearing members 22 are desirablyemployed. The bearing members .22 are shown most clearly in Figs. VII

and IX. They are preferably provided with a yoke-shaped body 33 and with crowned bearing surfaces 24 which engage rectangular retaining seats formed in the spring caps 25, 26, as shown most clearly in Fig. III. The retaining seats prevent relative shifting or turning of thefriction unit 3 about its vertical axis. Conveniently these seats may be formed by welding to the spring caps 25, 26 pairsrif spaced lugs 21 which accommodate between them the bearing members 22. Obviously other methods may be employed for seating the bearing members 22.. One advantage of the rockprojecting ears 23- which are perforated to accommodate the bolts 2|, and the bolts are held in place by nuts 23.

The vertically movable wedge members |4a, i4b, as shown most clearly in Fig. IX, are hollow and are adapted to receive in the interior thereof the major portionof eachbearing member 22. he vertically movable wedge members 14a, |4b are provided with central ribs 29, shown most clearly in Figs. VII and IX, which are rounded at the ends thereof and engaged by curved rocking surfaces of the yoke portions 33 of the bearing members 22. The wedge members I411, I411 are substantially ident1cal,in construction, and each member has friction surfaces 3| which are inclined inwardly from the sides of the unit toward the center thereof, and which are also inclined inwardly from the top and bottom of the unit toward the center thereof. In other words, the friction surfaces 3| of the wedge members (1, Mb are so'inclined as to converge in a horizontal plane and in a vertical plane toward the center of the unit. Each wedge member |4a, I4?) is provided with holes 32 through which the securing bolts 2| pass. Semi-circular recesses 33 are formed at the bottom of the upper member lla and at the top of the lower wedge member |4b to accommodate the horizontal retaining bolt 23.

Preferably each wedge member |4a, |4b is provided with laterally extending pins 34 which engage brackets 35, 36 on the spring caps 23', 23

of the car truck, as shown in Fig. II, and form As shown in Figs. II and III, the pins 34 of the lower wgdge member -|4b are engaged by'hookshaped brackets 33. The pins 3 wedge member |4a are engaged by additional hook-shaped brackets 35. In the event of sticking of the wedge members, the spring caps 25, 23 may become distorted, but the friction unit 3 will be held in place by engagement of the pins 34 with the brackets 35, 36. While I prefer to utilize such connections as a safety device to prevent dislodgment of the friction unit 3 under any condition, I do not wish to imply that the friction unit of this invention has a tendency to stick, for one of the important advantages of the invention is that it improves upon older forms of friction units in that the device of this invention is designed to minimize the possibility of the wedge members 4a, |4b failing to return to normal position under the influence of the springs I311, I312.

The horizontally movable wedge members l3a, |6b are shown most clearly in Fig.' IX. These of the upper members are substantially symmetrical and are provided with friction surfaces 33 which are complementary to the friction surfaces 3| of the v vertically movable wedge membersfla, llb, Like the friction surfaces 3|, the surfaces 33 converge inwardly in a horizontal and in a vertical plane toward the center of the unit. Desirably, the wedge member |3a at the rear of the friction unit 3 is formed with a central socket 33, in the present instance of hexagonal contour, for accommodating and. holding against rotation the head 43 of the bolt 23. Within the socket 33 and surrounding the bolt 23 there is provided a centering washer 54. From the socket 33 ribs 4| extend radially outward to the top and side edges. At the center thereof the wedge member'IGa is formed with a circular opening 42 for the passage of the bolt 23.

The companion wedge member lfib'is similar as to the formation of its inner face to the wedge member |6a. lit the center thereof there is a circular opening 43 far the passage of the bolt 23. At the front or outer face there are provided radial ribs 44, 45 an annular rib 43, and arcuate shown most clearly in Fig. III, the outer arcuate ribs 41 form a circular recess for the accommo-' dation of the end of the outer spring l3a. Likewise the inner annular rib 43 provides a circular recess for the accommodation of the inner spring l3b. At their outer ends the springs Ila, |3b of the friction unit 3 bear against a disk 43 which surrounds the bolt 23 and has an opening 43 through which the bolt passes. Desirably the disk 48 is formed with an annular boss 53 which fits within and serves to center theouter coil spring |3a. Moreover, the .disk 43 i s desirably also provided with a circular hub 5| which houses a centering washer" 52 and a lock nut 33 on the end of the bolt 23.

It will be noted that the'boits 2| maintain the vertically movable wedge members Ma, "12- in assembled relation, and that the horizontal bolt 20 and disk 48 thereon maintain the springs l8a, lb and the horizontally movable wedge members Ilia, 5b in assembled relation. The bolts also serve to establish limits for the travel of the wedge members, such limits being adjustable by means of the nuts 23, 53. Moreover, the angles formed between the inclined surfaces 38 and be-- tween the inclined surfaces 3| are such that the wedge members Ma, Mb, Ilia,'i6b, tend to maintain wedging engagement and to preserve contact over the entire friction surfaces.

The friction unit 9 of this invention. serves. to

break up the harmonic action of the coil springs rounded formation 'of the surfaces 24 of the bearing members 22. The bearing members 22 are so formed, as clearly shown in Fig. IX, that the vertically movable wedge members Ma, Mb are adapted to rock relatively thereto in a plane at right angles to the rocking plane of the friction unit. Vertical movement of the wedge members Ma, Mb produces horizontal movement of the wedge members lGa, Nib, the separation of the latter wedges being opposed by the springs l8a, I 8b. Thus the, line of action of the springs lBa, l8b, is at right angles to the line of action 'of the vertically movable wedge members Ma, Mb.

The parts of the friction unit 9 are characterized by relatively large fricti :1 surfaces, but are so designed as to reduce the endency to stick to a minimum. Moreover, advantage is taken of the entire space between the bolster l0 and the win dow seat for the wedge members of the friction unit, and advantage is taken of space outside of the windows of the side frames, and normally not utilized for any useful purpose, for'thesprings of the friction units. Thus the invention makes it possible to obtain the desired load carrying capacity by the use of large friction surfaces and without substantial change in existing car truck construction. In fact, ordinary car trucks may be converted or adapted to my invention by mere substitution of a friction unit for one or more of the coil springs and by minor changes in the spring caps.

While I have described in some detail an example of the practice of this invention, it will be apparent that changes may be made in the form of the apparatus herein described and illustrated without departing from the spirit of the invention as defined in the annexed claims. Particularly, it

i will be apparent that the friction unit may be dis- 1. In a car truck, a self-contained shockabsorbing unit including a pair of vertically movable wedge members, a pair of horizontally movable wedge members in frictional engagement with the vertically movable wedge members, vertically movable bearing members in engagement with parts of the car truck for transmitting the load to said wedge members, said bearing members having laterally extending ears disposed within the vertically 'movable wedge members,

bolts connecting the ears of one bearing member with the ears of the other bearing member, said bolts limiting the vertical separation of said bearing members and serving to maintain said vertically movable wedge members in assembled relation, and a spring opposing relative movement of said wedge members, said spring having a line of action at right angles to the line of action of said bearing members.

2. In a car truck, a self-contained shock absorbing unit including a pair of vertically movable wedge members, a pair of horizontally movable wedge members in frictional engagement with the vertically movable wedge members, top

and bottom bearing members for transmitting the load to said wedge members, and a spring opposing relative movement of said wedge members, each of said bearing members having rocking engagement with a vertically movable wedge member, and each of said bearing members having a rocking surface for engagement with parts of the car truck.

1 b. In a car truck, a self-contained shock absorbing unit including a pair of vertically movable wedge members, a pair of horizontally m'ovable wedge inembers in frictional engagement with theverticaliy'movable wedge members, top and bottom bearing members for transmitting the load to said wedge members, and a spring opposing relative movement of said wedge mem bers, each of said bearing members having rocking engagement with a vertically movable wedge member, and each of said bearing members having a rocking surface for engagement with parts of the car truck, the vertically movable Wedge members being adapted to rock relatively to the bearing members in a plane at' right angles to the rocking plane of the unit. 4. In acar truck, a side frame having a window therein, a bolster, and means for supporting 'the bolster on the side frame comprising coil springs disposed vertically beneath the bolster and a similarly disposed shock absorbing unit mounted between retaining seats on said bolster and side frame, and having movable wedge members in sliding 'frictionalyengagement, a spring opposing relative movement of said wedge members and projecting away from the window of the side frame in a substantially horizontal plane,

and bearing members having rocking engagement with parts of the car truck within said retainlng seats whereby incident to shifting of the bolster the load is transmitted substantially along the vertical axis of said shock absorbing unit, said retaining seats forming sockets for the accommodation of said bearing members and serving additionally to prevent said'shock "absorbing unit from turning abou its vertical axis.

CHARLE D. BARRETT. 

